Means for indenting radiator tubes



Aug. 17 ,1929.4 A 1,596,393

R. W. BYOWNE MEANS FOR NDENTING RADIATOR TUBES /5 FlgJa 20,31923Patented Aug.l 1 7, 1926.

UNITED STATES PATENT OFFICE.

RAYMOND W. BOWNE, OF LYNN, MASSACHUSETTS. ASSIGNOR TO UNITED STATES CAR-TRIDGE COMPANY, OE LOWELL, MASSACHUSETTS, A CORPORATION MASSACHU- SETTS.

MEANS FOR IN DEN TING-*RADIATOR TUBES.

Application led January 20, 1928. Serial No. 613,884.

This invention pertains to the manufacture of thin metallic tubes suchfor example as are employed in the manufacture of radiators for use withinternal combustion engines. and relates more particularly to means forforming indentations inthe cylindrical walls of such a tube-withoutcrushing, warping. or unduly straining the ma terial of the tube as awhole.

.ln order t'o break up the air stream lowing through such radiatortubes, it has been found expedient to provide projections upon the innersurfaces of the tubes which act as bal'lles' producing swirls and eddiesin the stream ot air so that substantially every molecule of the flowingair is brought into intimate, heat exchanging Contact with the tubewall. lVhen such tubes are formed from thin metal, as for exampleSeamless copper tubing 'such as may be produced by an extrusionprocess,Athe only practical mode of forming the battles or inwardly directedprojections, is to indent the tube by pressure from the outside, but asthese tubes are sometimes only .006 of an inch thick, it

is. manifestly dillicult t6 form the indentations without seriouslydistorting the tube as a whole or stressing the metal at lor near theindentatious to an undesirable degree. I0 The object of the presentinvention is accordingly to provide improved means capable of formingthe desired indentati'ons in suoli tubes accurately and expeditiouslyand' without damage to the tube as a'whole or 5 imposing undue strainupon the metal adjacent to the indentations, and embodying provisionsfor minimizing wear of the indenting elements as well as for adjustingsuch elements to compensate for any wear which may occur. In theaccompanying drawings a preferred embodiment of the invention isillustrated by way of example, and in such drawings:

Figure 1 is a fragmentary vertical cross P sectional view 'of a machineadapted for perforniing the indenting operation and embodying tuboclanlping and indenting elements constructed in accordance with thepresent invention. k

Fig. 2 is a front elevation of one of the clamping jaws of the machine'of Fig. 1,

showing the present improvements as applied thereto.

Fig. 3 is a horizontal cross section on the line 3-3 of Fig. 2 lookingin the direction parts of the tube being broken away for clearness inillustration; and

Fig. 8 is a side elevation of a completed j tube showing one series ofthe indentations formed therein.

The nume-ral 1 indicates the bed or table ofthe machine mounted uponlegs such as 2. and being provided with an opening or slot 3 for thedischarge ofthe completed tubes. A bracket 4i's secured to the table 1and vserves to support the fixed clamping jaw or block 5, hereinaftermore fully described. At the opposite side of the slot 3 the table orbed is furnished with a support 6 above which is mounted the bracket 7providing an inclined guideway or chute 8 for the tube blanks 9. Thebracket 7 is spaced from the support 6 to provide a guideway for aslidingmember 10 which is reciprocated in any desired .manner common tothe art.` A flanged portion 11 ofthe movable clamping jaw or block 12 issecured to the end of the slide member'lOby means of screws such as 11.

Referring' to Figs. 2, 3, and 4, the fixed clamping jaw or block 5 isshown as provided with a vsubstantially flat vertical face 13 preferablymachined off smoothly and true. A substantially semi-cylindrical recess14. is formed in this face extending transversely across the block 5with its axis substantially horizontal. A series of bores 15 is formedin the block 5 at either side of the recess 14. These bores arepreferably to the axis of the recess 27 perpendicular to the surface 13and .intersect the latter at the opposite edges of the recess 14. Asherein shown three 'of such bores are arranged at one edge of the recessand two at the other, the bores of the two series being staggeredrelatively to each other. These bores are internally screw threaded forthe reception of screws such as 16, and these screws are furnished with'substantially spherical heads or ends 1-7 cqnstituting die memberswhich project into the recess 14 at opposite sides thereof. In order toretain the screws 16 in properly adjusted position, plugs such as 16amay be inserted in the recesses behind the screws if desired.

Two or more bores 18 are also formed in the block 5 intermediate the twoseries of bores 15. These bores 18 open into the recess 14 at pointssubstantially midway between the edges of the latter, but where theyenter such recess they are-of reduced diameter. Pins 19 are arranged toslide within the reduced portions ofthe bores 18, and these pins areprovided with enlarged heads 20 which serve to limit outward movement ofthe pins. Springs 21 seated in the bores 18 tend normally to project thepins 19 into the recess 14, such springs bearing at their outer endsagainst a plate 22 secured to the block 5 by means of screws 23 (seeFig. 4). This plate in turn is provided with threaded openings for thereception of bolts 24 by means of which it is secured to the bracket 4as above referred to. A pair of bores 25 of small diameter is alsoprovided in block 5, such bores opening into the face 13 of the block toone side of the recess 14, the purpose of these bores being hereinafterdescribed.

Referring to Figs. 5 and 6 the movable clamping` block or jaw 12 isvshown as furnished with the finished vertical face 26 in which is formeda semi-cylindrical recess complemental to the recess 14. A pair of pins28 project from the surface 26 of the block 12 and are so spaced as toenter the bores 25 in the block 5 as the movable block 12 is broughtinto operative relationshi to the block 5. When the movable bloc isbroughtinto engagement with the fixed block 5, the semi-cylindricalrecesses' 14 and 27 t0- gether constitute a cylindrical tube-receivingchamber of a diameter substantially equal to the external diameter ofthe tube to be indented.

The block 12 is provided with a series of bores 29 which open into therecess 27 at points` substantially midway. between the edges of thelatter. These bores preferably extend substantially radially withrespect and are internally screw threaded for the reception of screwssuch as 30. As shown in Fig. 6 these screws are provided with endportions 31 whlch bear against and serve to posltlonballs 32constituting die members seated in the ends of the respective bores andwhich project into the recess 27. As shown in Fig. 5 the block 12 isprovided with four of the bores 29 and with a corresponding number ofballs Preferably these bores are so disposed that the two inner ones ofthe series of balls 32 lie in the same radial planes as the sphericalends 17 of the screws 16 at the lower edge of the recess 14 of the block5 as viewed in vFig'. 2. When the block 12 is moved toward the block 5,the spherical die members 17 of the block 5 would normally engage withthe face 26 of the block 12 and prevent close contact of the face 26with the face 13. To permit actual engagement of these faces, the face26 is provided with recesses 33 and 34 into which the die members 17 mayproject as the clamping jaws are brought into engagement.

In F ig. 7 ldie elements useful in forming hexagonal heads upon thetubes either during or after indentation thereof are shown. For thispurpose the female die elements 35, 36 are disposed at opposite ends ofthe block 13 cooperating with the corresponding male die elements 37having hexagonal end portions 38 which enter the ends of the tube andserve to expand such ends outwardly into heads of hexagonal form. Thesehead forming die elements, however, form no part of the presentinvention.

In the operation of the device the lowermost tube blank 9EL is releasedfrom the chute 8 and is engaged by the edges of the recess 27 of theblock 12. uitable means not shown, but common to the art, may beemployed for supporting ,the tube in this osition as the clamping block12moves to t e left and into engagement with the block 5. As the blockscome into engagement the spherical die elements 17 and 32 impress thecylindrical walls of the tube with indentations such as indicated at 40in Fig. 8. During this indentation of the tube the main body thereof isclamped firmly within the cylindrical chamber formed by the walls of therecesses 14 and 27 so that it is .impossible for the tube to bulge orwarp, out of its true cylindrical shape'under the pressure exerted bythedie elements. As these die elements are of spherical curvature they formsmoothly rounded depressions in the tube which merge grad` ually intothe main wall of the tube without producing any sharp line ofdemarcation such as might result in the formation of incipient cracks orlines of strain. By reason of the arched form of the tube, the pressureof a spherical die against its wall results in the production ofspherically curved depressions which are elongated in an axialdirection.

If it be desired to form the hexagonal heads upon the tube while thetube is 'clamped betweenl the blocks 5 and 12the dies 35, 36 and 37 maybe actuated to produce such hexagonal heads before the block 12 isretracted. -After the indentations have been formed, the block 12 isretracted and the pins 19, which have been depressed during theindenting operation, spring outwardly forcing the finished tube from therecess 14. In Fig. 8 the finished tube is shown as provided with thehexagonal heads and with the indentions 40 in its cylindrical surface.

When die elements of the type shown in Fig. 4 are employed, it is clearthat if the face 13 or the recess 14 of the clamping block become worn,the die elements may be retracted, and the face of the block plan-ed olito secure a new surface, after which the die elements may be advanced tonormal operative position. It is also clear that as the die elementsthemselves are worn they may be advanced by rotation of the screws 16 ormay be withdrawn and replaced by new ones. If the arrangement shown inFig. 6 be employed, the die elements 32, which consist of hardened steelballs, may readily be rotated when worn by retracting the screws 30slightly and turning the balls within the bores 29, whereupon thevscrews may be tightened to retain the balls-in position. Alternativelywith this latterarrangement, the balls may be left free t'o turn, sothat they will continuously present free surfaces for engagement withthe tube. It is contemplated that either or both forms of die may beemployed to the same machine as desired.

That I claim and desire. to secure by Letters Patent of the UnitedStates is:

1. Apparatus of the class described comprising tube clamping means, andmeans for forming a plurality of longitudinally spaced axially elongatespherically curved indentations in the wall of the tube. I

2. Apparatus of the class described comprising tube positioning means,and means for forming spherically curved axially elongate indentationsin the cylindrical walls 0f the tube. Y

3. Apparatus of the class described comprising tube holding means, andmeans for forming a plurality of series of longitudinally spacedspherically curved axially elongate indentations in the cylindrical Wallof the tube.

4. Apparatusof the class described comprising tube clamping means, andmeans for producing a plurality of circumferentially and symmetricallyspaced series of longitudinally spaced axially elongate, sphericallycurved. indentations in the cylindrical wall of the tube.

5. Apparatus of the class described comrising relatively movable tubeclamping jaws, one at least of said jaws having a plurality ofspherically curved projections for engagement with the cylindricalsurface of vthe tube for indenting the latter.

6. Apparatus of the class described comprising relatively movable tubeclamping jaws, and a removable die member having a spherically curvedtube indenting surface projecting from each of said jaws for engagementwith the cylindrical wall of 'a tube clamped therebetween.

7. Apparatus of the class described comprising relatively movableclamping jaws provided with complemental recesses forming atubereceiving chamber and series of longitudinally ,spaced sphericallycurved elements projecting into said chamber for indenting thecylindrical wall of the tube, one of said series comprising a lessernumber o f projecting elements than another serles.

8. Apparatus of the class described coinprising separa-ble elementsprovided respectively with complemental recesses constituting acylindrical tube receiving chamber, and three series of axiall spaceddie elements projecting inwardly fyrom the walls of said chamber forindenting the cylindrical wall of a tube positioned therein, said seriesbeing spaced substantially equally apart in a circumferentialdirection.v

9. Apparatus of the class described coinprising relatively movable tubeclamping jaws having complemental recesses forn'iing a tube receivingchamber, and series of die members projecting into said chamber andextending longitudinally thereof, said dies having 'spherically curvedtube engaging surfaces the die members of one series being staggeredrelatively to those of an adjacent series. c

10. Apparatus of the class described comprising relatively movable tubeclamping jaws having complemental recesses forming a cylindrical tubereceiving chamber. and a` plurality of independently adjustable d iemembers spaced symmetrically about the axis of said chamber, said diemembers having spherically curved tube engaging surfaces for indentingthe circumferential `wall of the tube.

11. Apparatus of the class described comprising a pair of tube clampingjaws, a series of die memberspprojecting from one jaw, and two-series ofdie members projecting mfrom the other jaw, belng so disposed as toengage the tube symmetrically with respect to its axis.

12. Apparatus of the class described comprising a pair of clamping jawseach having a substantially semicylindrical recess collectivelyconstituting a tube receiving chamber,.a die projecting from one of saidjaws into its recess at a point disposed substan- Itially midway betweenthe edges of the. recess, and dies .projecting from theother jaw atopposite edges of its recess.

13. Apparatus of the class described corni tuting complemental halves ofa tube receiving chamber, a series of longitudinally spaced die elementsprojecting from the wall of one of said recesses, said series beingspaced equally from the edges of the recess, and a series oflongitudinally spaced 'die elements'projecting from each edge of theother of said recesses. y

14. Apparatus of the class described comprising tube clamping elementsproviding a tube receiving chamber, a die element projecting inwardlyfrom the wall of said chamber, and means for adjusting said die elementto project to a greater or lesser extent from the wall of the chamber.

15. Apparatus of the class described comprising a clamping member havinga tube receiving recess therein, said recess having a cylindricallycurved wall, a die element normally projecting from the wall of saidrecess, and means permitting said die element to be withdrawn from therecess.

16. Apparatus of the class described comprising a clamping block havinga tube receiving recess therein and a bore opening into said recess, adie member positioned within the bore and normally projecting into therecess, and adjustable means for retain-y ing said die member inoperative position.

17. Apparatus of the class described comprising a clamping block havinga substantially semicylindrical recess in one face thereof for thereception of a tube and a plurality of axially spaced radially extendingbores opening into said recess, said bores being internally screwthreaded, a die member positioned within each bore and projectingintothe recess, and means engaging the screw threads of the respectivebores for holding the dies in operative position.

18. Apparatus of the class described com- `Iprising. complementallyrecessed elements providing aY substantially receiving chamber, seriesof axially spaced bores in said elements opening into said chamber, eachof said bores being internallyY screw threaded, a die member seated ineach bore and normally projecting into the chamber, and threaded meansengaging the respective bores for holding the'dies in operativeposition, dies of the several series being space'd symmetrically of thecircumference of the chamber.

19. Apparatus of the class described comprising a tube clamping blockhaving a semicylindrical recess therein and series of bores openin intosaid recess at the opposite edges thereo and die elements havingoperative surfaces of spherical curvature seated in the respective boresand projecting into the marginal portions of said recess.

20. Apparatus of the class described comcylindrical tube prising a pairof relatively movable tube clamping jaws having complemental recessesforming a tube receiving chamber, spherical die elements projecting fromsaid jaws into the chamber, and spring actuated. members associated withone of said jaws for ejecting the tube from the recess therein uponcompletion of the operation.

21. Apparatus of the class described comprising a pair of relativelymovable clamping jaws having complemental recesses forming a cylindricaltube receiving chamber, a

series of spherical die elements projecting into the chamber from theopposite edges of the recess in one of said jaws, and spring actuatedpins normally projecting into said latter recess between A`the series ofdie elements for ejecting the tube from said recess after the completionof the operation. Y

Signed by me at Lowell, Mass., this 6th day of Jan., 1923.

RAYMOND W. BOWW

